Madison buell



(No Model.) 2 Sheets.-Sh-eet 1.

' BUELL.

RHEUSI'AT FOR MULTIPLE TELEGRAPHY. No. 256,458. Patented Apr. 18, 1882.

2 Sheets-Sheet 2.

M. BUELL. RHEOSTAT FOR MULTIPLE TELEGRAPHY. No. 256,458.

(No Model.)

Patented Apr. 18, 1882.

PETERS, Pholaog p w wnlunnw. D. C

UNITED STATES PATENT OFFICE.

MADISON BUELL, OF BUFFALO, NEW YORK.

RHEOSTAT FOR MULTIPLE TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 256,458, dated April18, 1882.

Application filcdJanuary 23, 1882. (No model.)

To all whom t'tmay concern:

Be it known that I, MADISON BUELL, a citizen of the United States,residing at Buffalo, county of Erie, and State of New York, have madecertain Improvements in Itheostats for Duplex or Multiplex Telegraphy,of which the following is a specification.

The object of this invention is to improve the manner of regulating oradjusting the artificial lines or circuits in systems of duplex ormultiplex telegraphy; and the invention consists in introducing aninsulated and adjustable earth-circuit side by side of and throughoutthe entire length of the artificial lines in the rheostat.

In all systems of duplex and multiplex telegraphy a differentialarrangement of the transmitting and receiving instrun'ients is employed,and the. accuracy of the system depends upon an artificial circuithaving exactly the same electrical resistance and capacity as the realline.

In my invention I adjust for the variations of the insulation of themain line by merely adjusting the insulated artificial resistances ofthe earth-circuit until it equalizes the static condition of the mainline, thereby preventing the false signals which occur by what aretermed charge and discharge currents.

To this end my invention consists more esspecially in a new and improvedconstruction of the rheostat, in order that it may not only bear aproper proportion to the main line, so far as its adjustable resistancesare concerned, but also an adjustable and proper proportionalelectrostatic capacity, as fully hereinafter explained.

In the drawings, Figure 1, is represented a top plan of a rheostat, thebox cut off longitudinally, and without the cover being shown. Fig. 2 isa plan showing the invention in circuit.

Arepresents the box of the rheostat; B B B, three spools, this numberbeing suificient to show my invention.

As is well known, the rheostat, as usually constructed and used inconnection with duplex and multiplex telegraphy, consists of a series ofspools, B, of one wire, having resistances ranging from one ohm up toten thousand or more ohms, so as to give any resistance of a whole numberofoh ins up to the desired amount. The terminals of each of thespools are two pieces of brass fixed on top of the box containing thespools, with a space between each piece for the insertion of conicalbrass plugs, and which serve to throw the spools in and out of circuit.This construction is that in common use.

My improvement consists in so constructing a rheostat that each andevery spool shall have two wires side by side, instead of one. The endsof the first wire, a, of every spool are brought to their properterminal pieces b on the right-hand side of the top of the box. Thesecond wire, 0, of every spool is brought to its proper terminal piece(I on the left-hand side of the top of the box, as shown. By this arrangementthe second wire, c,orinductiveearthcircuit can be adjusted in thesame manner as the first wire, a, or usual artificial lines in the samespool.

In Fig. 2 the rheostat as thus constructed is connectedin duplextelegraph y as follows: The currents formed by each contact of thetransmitter (not shown, as any will do) by the line '3 are divided intotwo parts, as shown at 0, one portion going through a relay, 0, to themain line 4, and operating the receiving-instrument at the distantstation, the other portion passing through relay 0 to wire a (No. 1) 0tspools of rheostat, thence to earth E. The wire (No. 2) c is alsoconnected to earth.

In using the improved rheostat as thus constructed the first wire, a, ofthe spools is used for the artificial line or resistance in preciselythesamemannerasisusual. Bothterminalsof the second wire, 0, of thespools are connected with the earth, and in consequence of suchconnection the artificial line a or resistances are brought into closeproximity through any portion or throughout its entire length, andthereby by proper adjustment an electrostatic condition is, so far aspractical results are concerned,establishedinit-theartificialline. Bythis new, and I believe novel, arrangement in the rheostatofanadjustable earth-circuitalongside of or in close proximity to that ofthe artificial line a, or any portion thereof, as stated, the latterline a can be made to have an inductive capacity proportional to that ofthe main line, and when the proper adjustments are made upon bothwiresaandcof the rheostat the charge and discharge currents take placeequally upon the main and artificial lines and transmission of falsesignals is entirely obviated. All changes in the main-line insulationare compensated for by adjusting the resistances of theearth-circuit-that is to say, suppose the resistance of the artificialline a to be six thousand ohms corresponding to that of the main line,all insulation variations can be balanced by adjusting the resistance ofthe earth-circuit c anywhere from one ohm up to six thousand ohms, ormore, if necessary.

I claim 1. An adjustable artificial line or circuit which consists ofthe adjustable artificial linecircuit a and an adjustable artificialearth-cirv MADISON BUELL.

Witnesses:

J. R. DRAKE,

T. H. PARSONS.

